Ground-Source Heating. Nice to see that it’s getting more air time now, because it’s a great technology. I looked into it for our place last year, but determined that it would take a long time to pay for itself — far longer than we’re planning to stay in this house, and there’s no guarantee that it’ll increase the sale value of the place by an offsetting amount. If/when we build a place to settle down in permanently, we’ll definitely get it.